As someone who has worked as an actress, singer, fashion designer and everything in between, Jessica Simpson‘s biggest and most important job has still been Mom — but it hasn’t always been easy.
“Three is challenging. We are trying to get into the groove and make sure all three kids are getting equal attention … it’s more than a full-time job right now,” Simpson, 38, tells PEOPLE of her and husband Eric Johnson‘s dynamic with their kids: daughters Birdie Mae, 5 weeks, and Maxwell “Maxi” Drew, 7 next month, plus 5½-year-old son Ace Knute.
How she handles some of the more chaotic aspects of parenting two children and a newborn? “The other night, all three kids were crying at the same time, so I just joined in! Ha!” Simpson says.
The family is “doing well” through the household’s ups and downs, though — and everyone is equally “so in love” with the newest addition, baby Birdie, who stars in a few new snaps her parents share exclusively with PEOPLE.
Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter.
“[Birdie] makes our family complete,” says the new mom of three. “Someone once told me to keep in mind that everything is a phase with infants and kids … trying to remember that fact, and celebrate the small victories.”
Simpson says her baby girl — who arrived March 19 — is “very sweet,” “loves to be cuddled” and “is highly alert when she is awake.”
“However, when this girl needs something, she makes it known!” the star jokes to PEOPLE.
RELATED VIDEO: Jessica Simpson Shares Adorable New Photos of 4-Week-Old Birdie with Daughter Maxwell and Son Ace
Simpson shares that she and Johnson, 39, are “definitely more relaxed” with baby No. 3, after the “whirlwind” of having their first two children just over a year apart.
“We are trying our best to be as present as possible and enjoy every part of having a newborn,” she explains. “We know how fast the time goes and how precious it is.”
For more on Jessica Simpson’s new life as a mom of three, pick up the latest issue of PEOPLE, on newsstands Friday.